Because limited resources are a thing that exists? I think if you were to take a poll, most people would agree that throwing all our economic might behind prese

Because limited resources are a thing that exists? I think if you were to take a poll, most people would agree that throwing all our economic might behind preserving the one bastion of life we know of in the universe is a better course of action than spending our time and money on what for the foreseeable future remains a pipe dream to be smoked by the very few. In all likelihood, we will need the technologies developed in a green revolution to even have a fighting chance of success at colonizing other worlds.